LeetCode--Same Tree

题目:

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

代码:

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */

    bool isSameTree(TreeNode* p, TreeNode* q) {        if(p == NULL && q == NULL)        {            return true;        }        else if(p == NULL && q != NULL)        {            return false;        }        else if( p != NULL && q == NULL)        {            return false;        }        else        {            if(p->val == q->val)            {               return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);            }            else                return false;        }    }